Uterine fibroids are tumors that grow in a woman's womb (uterus). These growths are typically not cancerous (benign).
Uterine fibroids are common. As many as 1 in 5 women may have fibroids during their childbearing years. Half of all women have fibroids by age 50.
Fibroids are rare in women under age 20. They are more common in African-Americans than Caucasians.
No one knows exactly what causes fibroids. They are thought to be caused by:
- Hormones in the body
- Genes (may run in families)
Fibroids can be so tiny that you need a microscope to see them. They can also grow to be very large. They may fill the entire uterus and may weigh several pounds. Although it is possible for just one fibroid to develop, usually there are more than one.
Fibroids can grow:
- In the muscle wall of the uterus (myometrial)
- Just under the surface of the uterine lining (submucosal)
- Just under the outside lining of the uterus (subserosal)
- On a long stalk on the outside the uterus or inside the uterus (pedunculated)
Common symptoms of uterine fibroids are:
- Bleeding between periods
- Heavy bleeding during your period, sometimes with blood clots
- Periods that may last longer than normal
- Needing to urinate more often
- Pelvic cramping or pain with periods
- Feeling fullness or pressure in your lower belly
- Pain during intercourse
Often, you can have fibroids and not have any symptoms. Your health care provider may find them during a physical exam or other test. Fibroids often shrink and cause no symptoms in women who have gone through menopause.
Exams and Tests
Your health care provider will perform a pelvic exam. This may show that you have a change in the shape of your womb.
Fibroids are not always easy to diagnose. Being obese may make fibroids harder to detect. Your provider may do these tests to look for fibroids:
- Ultrasound uses sound waves to create a picture of the uterus
- MRI uses powerful magnets and radio waves to create a picture
- Saline infusion sonogram (hysterosonography) uses saline injected into the uterus to make it easier to see the uterus using ultrasound
- Hysteroscopy uses a long, thin tube inserted through the vagina and into the uterus to examine the inside of the uterus
If you have unusual bleeding, your provider may do one of these procedures:
- A small piece of the lining of the uterus is removed and checked for cancer (endometrial biopsy)
- The doctor inserts a small tube through a small cut in your belly to look inside your pelvis (laparoscopy)
What type of treatment you have depends on:
- Your age
- Your general health
- Your symptoms
- Type of fibroids
- If you are pregnant
- If you want children in the future
Treatment for the symptoms of fibroids may include:
- Birth control pills to help control heavy periods
- Intrauterine devices (IUDs) that release hormones to help reduce heavy bleeding and pain
- Iron supplements to prevent or treat anemia due to heavy periods
- Pain relievers for cramps or pain
- Hormone therapy shots to help shrink fibroids (done only for a short time)
- Watchful waiting: having pelvic exams or ultrasounds every once in a while to check the fibroid's growth
Surgery and procedures used to treat fibroids include:
- Hysteroscopy. This procedure can remove fibroids growing inside the uterus.
- Uterine artery embolization. This procedure stops the blood supply to the fibroid, causing it to shrink and die.
- Myomectomy. This surgery removes the fibroids from the uterus. This may be a good choice if you want to have children. It won't prevent fibroids from growing again.
- Hysterectomy. This surgery removes the uterus completely. It may be an option if you don't want children, medicines do not work, or you cannot have any other procedures.
The National Uterine Fibroid Foundation offers an online support group -- www.nuff.org
If you have fibroids without symptoms, you may not need treatment. Menopause typically causes fibroids to shrink.
If you have fibroids, they may grow if you become pregnant. This is due to the increased blood flow and higher estrogen levels. The fibroids usually return to their original size after your baby is born.
Some fibroids are cancerous (malignant). One rare type, called leiomyosarcomas, look exactly like fibroids. It can be difficult to tell the difference until they are surgically removed. There is a very small chance that a fibroid will actually be cancerous. Talk with your health care provider about this rare form of cancer.
Complications of fibroids include:
- Severe pain or very heavy bleeding that needs emergency surgery.
- Twisting of the fibroid. This can cause blocked blood vessels that feed the tumor. You may need surgery if this happens.
- Anemia (not having enough red blood cells) from heavy bleeding.
- Urinary tract infections. If the fibroid presses on the bladder, it can be hard to empty your bladder completely. Holding urine in your bladder too long can lead to infection.
- Infertility, in rare cases.
If you are pregnant, there's a small risk that fibroids may cause complications. These include:
- You may deliver your baby early because there is not enough room in your womb.
- If the fibroid blocks the birth canal or puts the baby in a dangerous position, you may need to have a cesarean birth (C-section).
- You may have heavy bleeding right after giving birth.
When to Contact a Medical Professional
Call your health care provider if you have:
- Heavy bleeding, increased cramping, or bleeding between periods
- Fullness or heaviness in your lower belly area
Leiomyoma; Fibromyoma; Myoma; Fibroids
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Update Date 11/16/2014
Updated by: Cynthia D. White, MD, Fellow American College of Obstetricians and Gynecologists, Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.